Set Categories as a read-only method and fix tests

app.go

@@ -37,8 +37,8 @@ type App struct {
 	HideVersion bool
 	// Display commands by category
 	CategorizedHelp bool
-	// Populate when displaying AppHelp
-	Categories CommandCategories
+	// Populate on app startup, only gettable throught method Categories()
+	categories CommandCategories
 	// An action to execute when the bash-completion flag is set
 	BashComplete func(context *Context)
 	// An action to execute before any subcommands are run, but after the context is ready
@@ -101,12 +101,12 @@ func (a *App) Run(arguments []string) (err error) {
 	}
 
 	if a.CategorizedHelp {
-		a.Categories = CommandCategories{}
+		a.categories = CommandCategories{}
 		for _, command := range a.Commands {
-			a.Categories = a.Categories.AddCommand(command.Category, command)
+			a.categories = a.categories.AddCommand(command.Category, command)
 		}
 	}
-	sort.Sort(a.Categories)
+	sort.Sort(a.categories)
 
 	newCmds := []Command{}
 	for _, c := range a.Commands {
@@ -329,6 +329,11 @@ func (a *App) Command(name string) *Command {
 	return nil
 }
 
+// Returnes the array containing all the categories with the commands they contain
+func (a *App) Categories() CommandCategories {
+	return a.categories
+}
+
 func (a *App) hasFlag(flag Flag) bool {
 	for _, f := range a.Flags {
 		if flag == f {

app_test.go

@@ -8,6 +8,7 @@ import (
 	"io"
 	"io/ioutil"
 	"os"
+	"reflect"
 	"strings"
 	"testing"
 )
@@ -939,6 +940,49 @@ func TestApp_Run_Version(t *testing.T) {
 	}
 }
 
+func TestApp_Run_Categories(t *testing.T) {
+	app := NewApp()
+	app.Name = "categories"
+	app.CategorizedHelp = true
+	app.Commands = []Command{
+		Command{
+			Name:     "command1",
+			Category: "1",
+		},
+		Command{
+			Name:     "command2",
+			Category: "1",
+		},
+		Command{
+			Name:     "command3",
+			Category: "2",
+		},
+	}
+	buf := new(bytes.Buffer)
+	app.Writer = buf
+
+	app.Run([]string{"categories"})
+
+	expect := CommandCategories{
+		&CommandCategory{
+			Name: "1",
+			Commands: []Command{
+				app.Commands[0],
+				app.Commands[1],
+			},
+		},
+		&CommandCategory{
+			Name: "2",
+			Commands: []Command{
+				app.Commands[2],
+			},
+		},
+	}
+	if !reflect.DeepEqual(app.Categories(), expect) {
+		t.Fatalf("expected categories %#v, to equal %#v", app.Categories(), expect)
+	}
+}
+
 func TestApp_Run_DoesNotOverwriteErrorFromBefore(t *testing.T) {
 	app := NewApp()
 	app.Action = func(c *Context) {}

help.go

@@ -48,8 +48,7 @@ USAGE:
 
 {{if .Category}}CATEGORY:
    {{.Category}}
-{{end}}
-DESCRIPTION:
+{{end}}DESCRIPTION:
    {{.Description}}{{end}}{{if .Flags}}
 
 OPTIONS: